/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.util;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.signature.SignatureVisitor;

/**
 * A {@link SignatureVisitor} that checks that its methods are properly used.
 * 
 * @author Eric Bruneton
 */
public class CheckSignatureAdapter extends SignatureVisitor {

  /**
   * Type to be used to check class signatures. See
   * {@link #CheckSignatureAdapter(int, SignatureVisitor) CheckSignatureAdapter}
   * .
   */
  public static final int CLASS_SIGNATURE = 0;

  /**
   * Type to be used to check method signatures. See
   * {@link #CheckSignatureAdapter(int, SignatureVisitor) CheckSignatureAdapter}
   * .
   */
  public static final int METHOD_SIGNATURE = 1;

  /**
   * Type to be used to check type signatures.See
   * {@link #CheckSignatureAdapter(int, SignatureVisitor) CheckSignatureAdapter}
   * .
   */
  public static final int TYPE_SIGNATURE = 2;

  private static final int EMPTY = 1;

  private static final int FORMAL = 2;

  private static final int BOUND = 4;

  private static final int SUPER = 8;

  private static final int PARAM = 16;

  private static final int RETURN = 32;

  private static final int SIMPLE_TYPE = 64;

  private static final int CLASS_TYPE = 128;

  private static final int END = 256;

  /**
   * Type of the signature to be checked.
   */
  private final int type;

  /**
   * State of the automaton used to check the order of method calls.
   */
  private int state;

  /**
   * <tt>true</tt> if the checked type signature can be 'V'.
   */
  private boolean canBeVoid;

  /**
   * The visitor to which this adapter must delegate calls. May be <tt>null</tt>
   * .
   */
  private final SignatureVisitor sv;

  /**
   * Creates a new {@link CheckSignatureAdapter} object. <i>Subclasses must not
   * use this constructor</i>. Instead, they must use the
   * {@link #CheckSignatureAdapter(int, int, SignatureVisitor)} version.
   * 
   * @param type
   *          the type of signature to be checked. See {@link #CLASS_SIGNATURE},
   *          {@link #METHOD_SIGNATURE} and {@link #TYPE_SIGNATURE}.
   * @param sv
   *          the visitor to which this adapter must delegate calls. May be
   *          <tt>null</tt>.
   */
  public CheckSignatureAdapter(final int type, final SignatureVisitor sv) {
    this(Opcodes.ASM6, type, sv);
  }

  /**
   * Creates a new {@link CheckSignatureAdapter} object.
   * 
   * @param api
   *          the ASM API version implemented by this visitor. Must be one of
   *          {@link Opcodes#ASM4}, {@link Opcodes#ASM5} or {@link Opcodes#ASM6}
   *          .
   * @param type
   *          the type of signature to be checked. See {@link #CLASS_SIGNATURE},
   *          {@link #METHOD_SIGNATURE} and {@link #TYPE_SIGNATURE}.
   * @param sv
   *          the visitor to which this adapter must delegate calls. May be
   *          <tt>null</tt>.
   */
  protected CheckSignatureAdapter(final int api, final int type, final SignatureVisitor sv) {
    super(api);
    this.type = type;
    this.state = EMPTY;
    this.sv = sv;
  }

  // class and method signatures

  @Override
  public void visitFormalTypeParameter(final String name) {
    if (type == TYPE_SIGNATURE || (state != EMPTY && state != FORMAL && state != BOUND)) {
      throw new IllegalStateException();
    }
    checkIdentifier(name, "formal type parameter");
    state = FORMAL;
    if (sv != null) {
      sv.visitFormalTypeParameter(name);
    }
  }

  @Override
  public SignatureVisitor visitClassBound() {
    if (state != FORMAL) {
      throw new IllegalStateException();
    }
    state = BOUND;
    SignatureVisitor v = sv == null ? null : sv.visitClassBound();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  @Override
  public SignatureVisitor visitInterfaceBound() {
    if (state != FORMAL && state != BOUND) {
      throw new IllegalArgumentException();
    }
    SignatureVisitor v = sv == null ? null : sv.visitInterfaceBound();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  // class signatures

  @Override
  public SignatureVisitor visitSuperclass() {
    if (type != CLASS_SIGNATURE || (state & (EMPTY | FORMAL | BOUND)) == 0) {
      throw new IllegalArgumentException();
    }
    state = SUPER;
    SignatureVisitor v = sv == null ? null : sv.visitSuperclass();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  @Override
  public SignatureVisitor visitInterface() {
    if (state != SUPER) {
      throw new IllegalStateException();
    }
    SignatureVisitor v = sv == null ? null : sv.visitInterface();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  // method signatures

  @Override
  public SignatureVisitor visitParameterType() {
    if (type != METHOD_SIGNATURE || (state & (EMPTY | FORMAL | BOUND | PARAM)) == 0) {
      throw new IllegalArgumentException();
    }
    state = PARAM;
    SignatureVisitor v = sv == null ? null : sv.visitParameterType();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  @Override
  public SignatureVisitor visitReturnType() {
    if (type != METHOD_SIGNATURE || (state & (EMPTY | FORMAL | BOUND | PARAM)) == 0) {
      throw new IllegalArgumentException();
    }
    state = RETURN;
    SignatureVisitor v = sv == null ? null : sv.visitReturnType();
    CheckSignatureAdapter cv = new CheckSignatureAdapter(TYPE_SIGNATURE, v);
    cv.canBeVoid = true;
    return cv;
  }

  @Override
  public SignatureVisitor visitExceptionType() {
    if (state != RETURN) {
      throw new IllegalStateException();
    }
    SignatureVisitor v = sv == null ? null : sv.visitExceptionType();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  // type signatures

  @Override
  public void visitBaseType(final char descriptor) {
    if (type != TYPE_SIGNATURE || state != EMPTY) {
      throw new IllegalStateException();
    }
    if (descriptor == 'V') {
      if (!canBeVoid) {
        throw new IllegalArgumentException();
      }
    } else {
      if ("ZCBSIFJD".indexOf(descriptor) == -1) {
        throw new IllegalArgumentException();
      }
    }
    state = SIMPLE_TYPE;
    if (sv != null) {
      sv.visitBaseType(descriptor);
    }
  }

  @Override
  public void visitTypeVariable(final String name) {
    if (type != TYPE_SIGNATURE || state != EMPTY) {
      throw new IllegalStateException();
    }
    checkIdentifier(name, "type variable");
    state = SIMPLE_TYPE;
    if (sv != null) {
      sv.visitTypeVariable(name);
    }
  }

  @Override
  public SignatureVisitor visitArrayType() {
    if (type != TYPE_SIGNATURE || state != EMPTY) {
      throw new IllegalStateException();
    }
    state = SIMPLE_TYPE;
    SignatureVisitor v = sv == null ? null : sv.visitArrayType();
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  @Override
  public void visitClassType(final String name) {
    if (type != TYPE_SIGNATURE || state != EMPTY) {
      throw new IllegalStateException();
    }
    checkClassName(name, "class name");
    state = CLASS_TYPE;
    if (sv != null) {
      sv.visitClassType(name);
    }
  }

  @Override
  public void visitInnerClassType(final String name) {
    if (state != CLASS_TYPE) {
      throw new IllegalStateException();
    }
    checkIdentifier(name, "inner class name");
    if (sv != null) {
      sv.visitInnerClassType(name);
    }
  }

  @Override
  public void visitTypeArgument() {
    if (state != CLASS_TYPE) {
      throw new IllegalStateException();
    }
    if (sv != null) {
      sv.visitTypeArgument();
    }
  }

  @Override
  public SignatureVisitor visitTypeArgument(final char wildcard) {
    if (state != CLASS_TYPE) {
      throw new IllegalStateException();
    }
    if ("+-=".indexOf(wildcard) == -1) {
      throw new IllegalArgumentException();
    }
    SignatureVisitor v = sv == null ? null : sv.visitTypeArgument(wildcard);
    return new CheckSignatureAdapter(TYPE_SIGNATURE, v);
  }

  @Override
  public void visitEnd() {
    if (state != CLASS_TYPE) {
      throw new IllegalStateException();
    }
    state = END;
    if (sv != null) {
      sv.visitEnd();
    }
  }

  private void checkClassName(final String name, final String msg) {
    if (name == null || name.length() == 0) {
      throw new IllegalArgumentException("Invalid " + msg + " (must not be null or empty)");
    }
    for (int i = 0; i < name.length(); ++i) {
      if (".;[<>:".indexOf(name.charAt(i)) != -1) {
        throw new IllegalArgumentException("Invalid " + msg + " (must not contain . ; [ < > or :): " + name);
      }
    }
  }

  private void checkIdentifier(final String name, final String msg) {
    if (name == null || name.length() == 0) {
      throw new IllegalArgumentException("Invalid " + msg + " (must not be null or empty)");
    }
    for (int i = 0; i < name.length(); ++i) {
      if (".;[/<>:".indexOf(name.charAt(i)) != -1) {
        throw new IllegalArgumentException("Invalid " + msg + " (must not contain . ; [ / < > or :): " + name);
      }
    }
  }
}
